Materials and Methods: MEDLINE, EMBASE, CINAHL, and Cochrane databases were searched from January 1966 to February 2006. Prospective trials were selected if they (a) compared graded compression US and CT in the same patient population; (b) included more than 10 patients, otherwise, the study was considered a case report; (c) evaluated mainly adults or adolescents; (d) used surgery and/or clinical follow-up as reference standard; and (e) reported data to calculate 2 x 2 contingency tables for graded compression US and CT. Estimates of sensitivity, specificity, and positive and negative likelihood ratios (LRs) for US and CT were calculated. Posttest probabilities after CT and US were calculated for various clinically relevant prevalences.

Results: Six studies were included, evaluating 671 patients (mean age range, 26–38 years); prevalence of acute appendicitis was 50% (range, 13%–77%). Positive LR was 9.29 (95% confidence interval [CI]: 6.9, 12.6) for CT and 4.50 (95% CI: 3.0, 6.7; P = .011) for US, yielding posttest probabilities for positive tests of 90% and 82%, respectively. Negative LR was 0.10 (95% CI: 0.06, 0.17) for CT and 0.27 (95% CI: 0.17, 0.43) for US (P = .013), resulting in posttest probabilities of 9% and 21%, respectively. Posttest probabilities for positive tests were markedly decreased at lower prevalences.

Conclusion: In head-to-head comparison studies of diagnostic imaging, CT had a better test performance than did graded compression US in diagnosing appendicitis. Ignoring the relationship between prevalence (pretest probability) and diagnostic value may lead to an inaccurate estimation of diagnostic performance.

Supplemental material: http://radiology.rsnajnls.org/cgi/content/full/2491071652/DC1

© RSNA, 2008

Materials and Methods: Diagnostic accuracy studies were identified by hand searching six STARD and six non-STARD journals for 2001, 2002, 2004, and 2005. Diagnostic accuracy studies (n = 240) were assessed by using a checklist of 13 of 25 STARD items. The change in the mean total score on the modified STARD checklist was evaluated with analysis of covariance. The change in proportion of times that each individual STARD item was reported before and after STARD statement publication was evaluated (² tests for linear trend).

Results: With mean total score as dependent factor, analysis of covariance showed that the interaction between the two independent factors (STARD or non-STARD journal and year of publication) was not significant (F = 0.664, df = 3, partial ² = 0.009, P = .58). Additionally, the frequency with which individual items on the STARD checklist were reported before and after STARD statement publication has remained relatively constant, with little difference between STARD and non-STARD journals.

Conclusion: After publication of the STARD statement in 2003, the quality of reporting of diagnostic accuracy studies remained similar to pre–STARD statement publication levels, and there was no meaningful difference (ie, one additional item on the checklist of 13 of 25 STARD items being reported) in the quality of reporting between those journals that published the STARD statement and those that did not.

© RSNA, 2008